Conventionally, in regard to a reel winding a tape, there is proposed a tape reel in which the reel is divided into a pair of right and left division reels having a core with an equal diameter inside the respective centers, a core having a small diameter is provided to one of the cores in a protruding condition, a hole into which the core having a small diameter is fitted is provided to the other opposite core, and the width of the reel may be changed by these fitting adjustment as disclosed in Japanese Patent Application Publication No. 5-43139 (Patent Document 1). Such a tape reel may support tapes having different widths.
In a magnetic tape cartridge and the like, there is a case where a tape wound around a reel becomes uneven due to vibration, impact, temperature and humidity. Especially, in recent years, the length of a magnetic tape wound around a reel tends to become longer to increase the storage capacity per reel. Accordingly, the thickness of a magnetic tape becomes thinner. As a result, the strength of a magnetic tape decreases. Thus, once the winding step of a tape occurs, edge folding of a magnetic tape tends to occur.